Sinn Féin is to back a unionist candidate in the upcoming Seanad by-election.

Mary Lou McDonald has confirmed that TDs and senators have been told to vote for the ex-president of the Ulster Farmers’ Union Ian Marshall.

Mr Marshall is running as an Independent candidate for one of two vacancies – but put his name forward following an approach from Taoiseach Leo Varadkar.

He was a strong anti-Brexit campaigner and currently works in Queen’s University in Belfast.

Ms McDonald met with him on several occasions in recent weeks and said she was “impressed by his views on Brexit and the potential impact Brexit will have on the island, north and south”.

“I believe Ian will be a strong Independent voice in the Seanad; providing an anti-Brexit unionist perspective, which is a welcome addition to the political discourse surrounding the issue in the Oireachtas.

“Brexit affects people from all backgrounds and ways of life; nationalist, unionists and everyone in between,” she said.

The move means Mr Marshall looks almost certain to secure a seat in the Upper House.

“Ian is a unionist. I am an Irish Republican. As I have stated repeatedly, the Ireland I want to see is one where one can comfortably be Irish or British, both or neither.

“I believe Ian can bring a new and interesting voice to the discussion surrounding a New Ireland,” Ms McDonald said.

Voting in the bye-elections to fill the seats vacated by Denis Landy and Trevor Ó Clochartaigh is due to conclude on Friday.